Effects of different penetration-grade asphalt binders on the microstructure, mechanical, and aging properties of cold-mixed epoxy asphalt binder

The aim of this research was to investigate asphalt effects on the storage stability, mechanical properties and micro-properties of cold-mixed epoxy asphalt binder (CEAB). Firstly, four CEAB were prepared with four base asphalt types and storage stability, miscibility analyses were performed by fluorescence microscopy (FM). Then, cured CEAB and epoxy resin (ER) were treated by ultraviolet aging. Tensile test, dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy were applied to clarify the mechanical properties and micro-properties of aged and unaged CEAB. Also, bending beam rheometer (BBR) tests were conducted to study low-temperature performance of CEAB. The results revealed that the CEAB prepared with asphalt with penetration grade 60 similar to 80 presented superior storage stability, miscibility, mechanical properties and that prepared with penetration graded 80 similar to 100 showed slightly better low-temperature performance. Moreover, asphalt properties were found to have little impacts while epoxy resin played a key role in the mechanical properties of CEAB. Glass transition temperature (T-g) of the CEAB containing penetration-graded asphalt 80 similar to 100 decreased more significantly than that with penetration-graded asphalt 60 similar to 80, and it was also found that the CEAB prepared with base asphalt with higher molecular weight polydispersity index had better ductility performance.